Latest Articles
Research Article | Host-Microbe BiologyThe Monothiol Glutaredoxin Grx4 Regulates Iron Homeostasis and Virulence in Cryptococcus neoformansFungal pathogens cause life-threatening diseases in humans, particularly in immunocompromised people, and there is a tremendous need for a greater understanding of pathogenesis to support new therapies. One prominent fungal pathogen, Cryptococcus neoformans, causes meningitis in people suffering from HIV/AIDS. In the present study, we focused on characterizing...
Research Article | Molecular Biology and PhysiologyPotent Cas9 Inhibition in Bacterial and Human Cells by AcrIIC4 and AcrIIC5 Anti-CRISPR ProteinsAs one of their countermeasures against CRISPR-Cas immunity, bacteriophages have evolved natural inhibitors known as anti-CRISPR (Acr) proteins. Despite the existence of such examples for type II CRISPR-Cas systems, we currently know relatively little about the breadth of Cas9 inhibitors, and most of their direct Cas9 targets are uncharacterized. In this work we identify two new type II-C anti-CRISPRs and their cognate Cas9 orthologs,...
Research Article | Host-Microbe BiologyMicrobiota and Pathogen Proteases Modulate Type III Secretion Activity in Enterohemorrhagic Escherichia coliThe gut microbiota is usually regarded as providing colonization resistance against enteric pathogens. However, some pathogens evolved to thrive with the aid of certain members of the microbiota. Several Gram-negative bacteria employ type three secretion systems (T3SSs), which are molecular syringes that deliver effector proteins to host cells, hijacking host cell function. Here we show that the T3SS of enterohemorrhagic...
Research Article | Molecular Biology and PhysiologyAvoidance of Trinucleotide Corresponding to Consensus Protospacer Adjacent Motif Controls the Efficiency of Prespacer Selection during Primed AdaptationAdaptive immunity of prokaryotes depends on acquisition of foreign DNA fragments into CRISPR arrays as spacers followed by destruction of foreign DNA by CRISPR interference machinery. Different fragments are acquired into CRISPR arrays with widely different efficiencies, but the factors responsible are not known. We analyzed the frequency of spacers acquired during primed adaptation in an...
Research Article | Host-Microbe BiologyCryptococcus neoformans, Unlike Candida albicans, Forms Aneuploid Clones Directly from Uninucleated Cells under Fluconazole StressThe gold standard of cryptococcosis treatment consists of induction therapy with amphotericin B followed by lifelong maintenance therapy with fluconazole (FLC). However, prolonged exposure to FLC induces the emergence of clones heteroresistant to azoles. All the heteroresistant clones thus far analyzed have been shown to be aneuploids, but how the aneuploid is formed remains unclear. Aneuploidy in fungi and other eukaryotic cells is...
Commentary | Molecular Biology and PhysiologyBacillus subtilis Biofilms: a Matter of Individual Choice...Bacillus subtilis has the capacity to choose between two mutually exclusive lifestyles: biofilm formation and flagellum-mediated swimming motility. Interestingly, this choice is made at the individual cell level, with bacterial cells in a population expressing genes required for biofilm formation or genes required for swimming motility but not both.
Research Article | Ecological and Evolutionary ScienceOrigins and Evolution of the Global RNA ViromeThe majority of the diverse viruses infecting eukaryotes have RNA genomes, including numerous human, animal, and plant pathogens. Recent advances of metagenomics have led to the discovery of many new groups of RNA viruses in a wide range of hosts. These findings enable a far more complete reconstruction of the evolution of RNA viruses than was attainable previously. This reconstruction reveals the relationships between different...
Research Article | Ecological and Evolutionary ScienceSalmonella enterica Phylogeny Based on Whole-Genome Sequencing Reveals Two New Clades and Novel Patterns of Horizontally Acquired Genetic ElementsRapid improvements in nucleotide sequencing access and affordability have led to a drastic increase in availability of genetic information. This information will improve the accuracy of molecular descriptions, including serovars, within S. enterica. Although the concept of serovars continues to be useful, it may have more significant limitations than previously...
Research Article | Therapeutics and PreventionDevelopment of Thermostable Lyophilized Sabin Inactivated Poliovirus VaccinePoliomyelitis is a highly contagious disease caused by the poliovirus. While the live attenuated OPV has been the vaccine of choice, a major concern is its ability to revert to a form that can cause paralysis, so-called vaccine-associated paralytic poliomyelitis. Therefore, the new endgame strategy of the Global Polio Eradication Initiative includes the introduction of an IPV. However, the feasibility of the use of current IPV...
Research Article | Molecular Biology and PhysiologyMechanistic Basis for Decreased Antimicrobial Susceptibility in a Clinical Isolate of Neisseria gonorrhoeae Possessing a Mosaic-Like mtr Efflux Pump LocusHistorically, after introduction of an antibiotic for treatment of gonorrhea, strains of N. gonorrhoeae emerge that display clinical resistance due to spontaneous mutation or acquisition of resistance genes. Genetic exchange between members of the Neisseria genus occurring by transformation can cause significant changes in gonococci that impact the structure...